Pele

iTrader: (28)

I'd really like to help, but I dunno the difference between MDF and plywood. Well, I know what each is, but I dunno why you'd use MDF over plywood or particle board. That, and I dunno how to calculate the port sizes or anything.

Like I said, I'd pay good money... well maybe not Good money, but money... for something like that though.

MIKE-P-28

iTrader: (1)

Ok guys formulas for figuring box sizes, 3db down point and tuning frequencies isnt a mysterical form of calculus or black magic math

Vb=box volume
Fs(Fo)=free air resonance of the woofer (given in the Thiel and small parameters of the woofer)
Fb=Tuning frequency
VAS=Volume of Acosutic Suspension (or compliance) another given Thiel and small parameter)
F3=3 db down (this is where the woofer/box combo is 1/2 as loud/begines declining in SPL)
Lv=Vent length

Ok to figure volume:

Vb=(L X W X H)/1728=#ft3 if a rectangle
Vb=1/2(bXw) X h / 1728=#ft3 if its a triangle
Vb=(pi X r2)XL =#ft3 if its a cylinder
refer to other elementary geometry equations for other shapes remember to subtract displacement of the woofer and any internal bracing in the enclosure from the total volume before figuring f3's or fb's

Now to figure 3db down point of woofer

f3=(sqr(vas/vb))Xfs

Now to figure tuning frequency:

Fb=((vas/vb)to the .32 power) X fs

Now when you get the Fb heres the figuring of the port:

Lv=(8865Xr2)
---------- - 1.93(r) r=radius of the vent
(fb2 X fs)

There are common sense rules to apply to this, but you get the general idea, dont try to port a 12" sub in 1/2 cu ft. It dont work

Imagine when I went to JL audio seminar, the instructor picked on me, cause I was sleeping in the class. (I had worked all day before the meeting ) He said hey you in the back, whats the vent diameter and vent length for this 12w6 in 1 1/2 ft3 I just laughed and said give me a calculator 10 seconds later I told him, he looked it up in a namogram and I was with .05% He said you may leave if you want to, but come back at the end of class and tell me how you did that

No one needs computers all you need is a scientific calculator

Max7

If someone wants to make them for the group out of fiberglass. I will loan my fiberglass ones to have a mold made.
Mine were made with front and back molds, then molded together, so you would need to make 4 molds, Front and Back of both Left and Right.
You will need to remove the jack and the jack mount to make them fit, they are a perfect fit, and even have indents for the tailight bolt/nut ends.

These subs boxes are RARE and one of my most prized possesions, so they will not go to any fly by night person, and a cash deposit may be required for thier safe return

brownmound - The shelf paper helped to make them fit snugly, there was a wee bit of gap around them, and the soft rubber shelf paper fit the bill at the time

brownmound

Say Max I ain't knocking your boxes, I'm just jealous. I was curious about the shelf paper though, looks like the stuff we used to have back in the 80's. I guess since you cannot see them it doesn't really matter.

I like the look of Bad ***'s though, they look real clean. Is that MDF or fiberglass? Like I said I've never worked with figerglass before and I dont really want to. MDF seems a lot cleaner and lends itself more to the way I like to do things (exactly, to the nearest 32nd of an inch, in Autocad.)

I haven't gotten in there and started taking measurements yet, but from what I can see it looks like the boxes are similar to a rectangular prism with a corner cut off. Doesn't seem too too hard. Of course now that I think about it, it is another godawful position to work in - can't wait to see how long my back lasts leaning over the hatch.

I don't really see the need for me to make these things to sell, but I would be more than happy to, like I said earlier, document everything for others to use. Since I will probably do plans up in CAD I wouldn't mind making those available for others as well.

Looks like we have a couple people that want to make these. I say we all give it ago and see who comes out on top!

Right on.

PS: RotorMotorDriver, you ever get subs in that box you were designing? There was huge discussion back in that thread, I'd like to know how they came out.

Right on.

mar3

iTrader: (8)

RMD got a new toy, so we were left with his "art" subs sprayed on the finished box...I gots two old Pyle 10" subs he can have if he'll send his address and shipping money via PM...well, the address, anyhoos...

BadAssRX-7

ok heres a little more info and then ill get down to buis. if you look VERY close you can see that there is a false floor in my hatch... a 3/4 slab of mdf with carpet on it...sitting on the spare tire. really 1 reason that i have this. i wanted the hatch LEVEL... and the amp rack is 23/4 tall or so.... thats why the subs look almost under the red carpet. it just makes the hatch look so much cleaner being nice and flat. The pass. side is just like max said...you have to remove the stock jack and jack holder...eazy work with a hammer and a chisel.
now the boxs i have are made for the L7 subs i cant find the older pics i had of my OLD solos the round kind the box was shaped diffrent and was smaller. so the only way id sell them is to fit a L7 sub so i can copy my boxs. if anybody wants them let me know. they are MdF not fiberglass. and they are sealed. the L7's are POWER HUNGERY im running almost 2000 watts to the pair...when bridged down. and they love it. and then its great to sit in a lot and have some tunes going and people ask what i have..... what do you see? there you go its all stock.....till you see the 2 big amps. hell pop the hatch and with the tunes off they dont even know anythings there. I had the 1st set made for 300$ each but that included a old solo(100) the new L7 boxs were 200 each and then the subs were extra. ill copy them for 75 each plus shipping and ill seal the outside of the box, i did this cus 1 of the rain guards busted on my 1st set and the box got wet and i blew the side off with base...that was cool to see it go. theres a little play in the box but if you covered it with a thin carpet then its a nice TIGHT(tap it with a hammer) fit and it gonna be fun if someboduy wants to steal them, cuz you have to remove the side trim to install and remove them.

Directfreak

iTrader: (2)

I am interested. I love L7's, but I have always had Solo-Baric 10's and 12's. I don't know if L7's would offer enough deep bass for my taste. I will go to a Stereo shop and sample some L7's.

I love your install. Well done.

Directfreak

iTrader: (2)

Hey Brownmound..(or other Autocad wizard)

Since you are knowledgeable in AutoCad, could you help me out? (I have ZERO knowledge)

Here is a preliminary Subwoofer Design that I have been working on and off for my 7.

It is for a first Gen, to carry an L7 (10"), and component pairs for the front (probably 6 1/2"), with an amp rack between the front speakers. The L7 will use a maximum 1' cubic foot in a sealed chamber in the middle.

I want to make it all with a "Quick Disconnect" up in the front of the box, so I could always take it out for track events.

The front part of the footprint is slightly longer so it will pretty much wedge itself in to avoid additional bracing.
It will rest all the way forward, between the wheel wells.

What I need is an AutoCad drawing with more precise shapes, angles, sizes, etc - so I can have it built to my specs. My math needs work.

Feel free to post it when you finish, I don't mind sharing the goods.

Thanks in advance.

Here are the Kicker technical Manuals if you need them.

Directfreak

iTrader: (2)

Forgot to attach the file..

Duh.

EDIT:

It won't take PDF either!!...

Well, its in PDF, after being Zipped.

Max7

I just went and weighed one of the enclosures with the sub, tipped the scale at 10lbs per side. not to bad.
Can't find where its listed how much the speakers weigh

alien_rx7

I believe the uniform density of MDF is much higher than plywood or particle board (maybe thinking of chip board?). All three types of woods have air pockets, though MDF is an extremely small percentage. The creation of MDF by mixing long fibers with glue as it is created lends itself to a higher overall density and a better resistance to acoustical vibration and warping. Also, vibration can seperate the layers in plywood or chip board and create very annoying buzzing sounds that are hard to track down...

The last box I built was for a pair of 15" MTX's. We went to the local yard to get 3/4" MDF in 8'x10' sheets. We paid and told they would be brought around. Guess there was a mistake in their database and they had none on hand. They ended up giving us HDF for the same price as the MDF. What a buy!! Two to three times heavier and more dense this created a very solid box and sound!

brownmound

Um, are you for serious? I hope I'm getting paid to do this! We usually charge only $65/hr I think for drafting services. Just kidding.

For real though, I'd like to help you but I don't really have the time to interpret your design and try to draw it up in cad. The last time I used cad on my car was to install the nakamichi head unit. I was using plexi and I wanted the head unit face to be approx flush with the face of the plexi. I used a stock stereo bracket from a junkyard. I figured out what all the dimensions needed to be, drew it up in autocad and created templates on adhesive paper. That way I just stuck them to the bracket and I knew where to drill holes precise like. I also used it to cut the hole in the plexi.

click here if you want to see

For your sub box, I'm not sure you really need templates like I did. Just draw it on paper w/ dimensions and give it to who you want to build it, as it sounds like someone else is doing it (?). As fas the box design, it looks ok, except for it seems you are putting your soundstage right behind your heads, firing at the back of th seats. Ok if you like to listen to music like that. But most people don.t I've heard the sub firing at the glass is good though. Personally I am trying to keep a stealth look, that is why I am going to use the tailight location. Probably really wont need CAD for it though I will probably use it anyways just to lay out the pieces. It is easier in CAD to figure angles and space things out, you are right about that.

So, them 8" Kicker L7 have a lot of punch eh? I need to start shopping for subs.

Right on.

Pele

iTrader: (28)

I know how to figure volume. Where do you get all the other information from? Tuning Frequency? Free air resonance of the speaker? WTF is a Theil?

All the subs I've ever seen only say 8 Ohm or 4 Ohm on the back... Nothing else, except maybe the rare magnet weight and brand name.

I just know how to hook it up and that I want both a good punchy bass as well as a strong sustaned bass note. I need it to have a good frequency range. It does me no good if the sub only sounds good for rap or only at 72Hz or something...

I listen to all kinds of music, but mainly rock, which is diverse on it's own. Everything from Abba to Zeppelin, Led; Everything from the Pink Floyd to Papa Roach.

Directfreak

iTrader: (2)

Oh well. It was worth a try
I am not worried about the soundstage, as I will have door mounted 6 1/2's. The rear speakers are mostly for rear fill. I will send my drawing over to someone who is good at this sort of thing (ya hearing me Mike?) to see if I can get it broken down for the right dimensions and angles.

Thanx anyway Mound.

MIKE-P-28

iTrader: (1)

All of the Thiel and Small paramters will come with the new woofer... Ever read a sub woofers owners manual? LOL

Thiel and Small are 2 guys that came up with the definitions of terms for loudspeakers, and there measurements are basis for the Helmholtz resonator formulas I gave you

Pele

iTrader: (28)

So I have to build the box for the sub specifically, I can't just build a box for a generic 8" sub and go out shopping around for Cerwin-Vega's or Kicker's or Whatever.

So, if I get the sub and I build the box, and install the sub, but don't like it, I've wasted my money on the MDF and the time building the box.

I think I need to research a little more, and quit getting used equipment without manuals.

I don't wanna end up with something I can't use or looks like crap, or both.

MIKE-P-28

iTrader: (1)

I only gave you formulas for porting a box Thats all they were, and by all means yes you can build a box then shop for woofers.

Just remember the only way to tune a sealed box is with size. But with a sealed box you have several advantages, ease of construction, relative inhibition as to size (you can be way off and get a good response), holds tons of power, smooth roll off... Only 2 disadvatages I can think of 1) arent quite as efficient as a ported design, and 2) no tuning ability other than size (although darcon polyfill works quite well) ...Thats why a sealed box is the oldest box in the book

Pele

iTrader: (28)

Tell me more.

Max7

"But with a sealed box you have several advantages, ease of construction, relative inhibition as to size (you can be way off and get a good response), holds tons of power, smooth roll off"

Thats why I've always gone for Sealed boxes vs. Ported.
I'll save the porting for the motor

MIKE-P-28

iTrader: (1)

I could tell a lot more, but i dont feel like typing an entire book, and I bet im kinda unable to dump 12 years of experience in a few minutes

BadAssRX-7

well i think you need to get the sub then build the box... i know the solos are the smallest sealed box sub out , or atleast the last i knew they were. and if you get the box to big or to small it sounds like ****, and a solo is a SUB SUB . very low hz 28-100 and 300 rms with dual coils thats the l5 the l7 is 450rms

brownmound

For serious, it looks like you already have the outside dimensions of the box figured out. What more do you need? Just start cutting. Let me know how that **** comes out.

I'm gonna investigate into the dimensions of the tailight box this weekend. If it's nice, I'm hitting up some nature.

Right on.

brownmound

So you have what two L7's in two sealed boxes? And they hit pretty hard or what? What kind of music do you listen to?

As for diversity, today in the Mound I banged Felix the Housecat, Hall and Oates, Bobby Digital and the Promise Ring. But I like it punchy. Boomy would be good for screw, but punchy much better for house.

Sweet. Let's prove Mar3 wrong and get some boxes built.

Right on.

BadAssRX-7

i have all kinda of music in my car... from garth brooks(not in to to much cuntry) to alternative to bass to just about anything. Im very happy with my setup but i could use a little more midbass fillin. i have th2 8" L7's, 6.5" kenwood excelon rears and infinity 4.0 componants up front. with a ps 501 and ps301 excelon amps driving it and a kenwood comp. deck ...i think its a 915. its LOUD but could use a little more midbass if i wanted to be picky any oh yea it rocks pretty good. im not into killing everybodys ears or letting you hear me 20 miles away. so i think this set up is great. its COMPACT and sounds great

BadAssRX-7

the only none stealth part. but you have to keep them out so they can cool. Im working on making the rack a wee bit taller so i can make covers for the amps and then you wont see them at all.